diff --git a/tests/testSchema.xsd b/tests/testSchema.xsd
index 90b4f3e..bb4ab73 100644
--- a/tests/testSchema.xsd
+++ b/tests/testSchema.xsd
@@ -121,11 +121,27 @@
 				</xs:annotation>
 			</xs:element>
 
-			<xs:element name="expression" type="Expression">
+			<xs:choice>
 				<xs:annotation>
-					<xs:documentation>The expression to be tested.</xs:documentation>
+					<xs:documentation>
+						The item under test: either a single CQL expression, or a complete CQL library.
+						Exactly one must be provided. Use 'library' instead of 'expression' when the test
+						requires library-level declarations (e.g. function overloads, parameters, includes,
+						or multiple named defines); the expected results are then matched to the library's
+						defines via the 'name' attribute on 'output'.
+					</xs:documentation>
 				</xs:annotation>
-			</xs:element>
+				<xs:element name="expression" type="Expression">
+					<xs:annotation>
+						<xs:documentation>The expression to be tested.</xs:documentation>
+					</xs:annotation>
+				</xs:element>
+				<xs:element name="library" type="Library">
+					<xs:annotation>
+						<xs:documentation>The complete CQL library to be tested.</xs:documentation>
+					</xs:annotation>
+				</xs:element>
+			</xs:choice>
 			<xs:element name="output" type="Output" minOccurs="0" maxOccurs="unbounded">
 				<xs:annotation>
 					<xs:documentation>The expected output of the test.</xs:documentation>
@@ -199,6 +215,24 @@
 			</xs:extension>
 		</xs:simpleContent>
 	</xs:complexType>
+	<xs:complexType name="Library">
+		<xs:annotation>
+			<xs:documentation>
+				A complete CQL library provided as the body of the test. The content is the CQL source
+				text (including the 'library' declaration and any defines/functions). Results are matched
+				to individual defines via the 'name' attribute on the test's 'output' element(s).
+			</xs:documentation>
+		</xs:annotation>
+		<xs:simpleContent>
+			<xs:extension base="xs:string">
+				<xs:attribute name="invalid" type="InvalidType">
+					<xs:annotation>
+						<xs:documentation>Indicates whether the library is expected to translate/evaluate successfully, or to produce a syntax, semantic, or runtime error.</xs:documentation>
+					</xs:annotation>
+				</xs:attribute>
+			</xs:extension>
+		</xs:simpleContent>
+	</xs:complexType>
 	<xs:complexType name="Output">
 		<xs:simpleContent>
 			<xs:extension base="xs:string">
@@ -207,6 +241,11 @@
 						<xs:documentation>The type of the expected output. If output type is not present, the content of the output is the string representation of a literal (e.g. 10.0)</xs:documentation>
 					</xs:annotation>
 				</xs:attribute>
+				<xs:attribute name="name" type="xs:string" use="optional">
+					<xs:annotation>
+						<xs:documentation>For library-style tests, the name of the define whose expected result this output describes (corresponds to a 'define' statement in the library). Omitted for single-expression tests.</xs:documentation>
+					</xs:annotation>
+				</xs:attribute>
 			</xs:extension>
 		</xs:simpleContent>
 	</xs:complexType>